Dynamic Impact Analysis Research Articles

Passive Safety of a Buggy-Type Car in the Aspect of a Dynamic Analysis of the Frame

Abstract This article presents passive safety issues of a buggy-type car. The issue has been presented in the context of the dynamic impact analysis of the aluminium frame of the vehicle into a rigid wall. The study was conducted using the finite element method in the Abaqus® software. With regard to numerical calculations, a dynamic impact simulation was performed, which defined the critical areas of the structure. Numerical analysis allowed to obtain both the state of the strain of the frame structure and the characteristics of the construction work during the impact. The results of the research provide high-quality prepared FEM model.

Dynamic Fracture Analysis of High-speed Impact on Granite with Peridynamic Plasticity

Dynamic Fracture Analysis of High-speed Impact on Granite with Peridynamic Plasticity

Dental trauma on primary teeth at different root resorption stages-A dynamic finite element impact analysis of the effect on the permanent tooth germ.

Dental trauma is a common emergency in children with primary teeth. The aim of this study was to determine stress propagation to the permanent tooth germ and surrounding bone and soft tissues during dental trauma to primary central incisors with three levels of physiological root resorption. Stresses were determined using finite element analysis (FEA). Cross-sectional models were created using cone-beam computed tomography images of 3.5, 5, and 6years olds, representing three different physiological root resorption stages of a maxillary primary central incisor. The models included periodontal ligament, bone, and soft tissues. An impact with an asphalt block moving at 1m/s,was simulated for two impact two directions, frontal on the labial tooth surface, and on the incisal edge. Stresses and strains were recorded during impact. The impact caused stress concentrations in the surrounding bone and soft tissues and permanent tooth germ, regardless of the direction of impact and the primary tooth resorption stage. Impact stresses in dental follicles and surrounding bone increased in models with more physiological root resorption of the primary tooth. Incisal impact generated higher stress concentrations in surrounding bone and soft tissues and permanent tooth germ regardless of physiological root resorption stage. The primary incisor with no physiological root resorption showed high stress concentrations at its root apex. During impact to a primary incisor, stresses most significant for potential damage to the formation of permanent enamel and dentin were at the dental follicle and surrounding bone tissue with the three levels of physiological root resorption.

Three-dimensional finite element stress analysis of teeth adjacent to a traumatized incisor.

Dental trauma is the cause of several consequences to the injured tooth. However, the stresses and strains at adjacent teeth non-directly impacted as a possible cause of sequelae are still unknown. The aim of this study was to evaluate the stress distribution in incisors adjacent to an upper central incisor when it suffers a frontal impact in order to identify a potential explanation for sequelae in non-traumatized teeth. A three-dimensional (3D) finite element model of the maxillary central incisors, lateral incisors and canines was created from a cone-beam scan of a patient with normal occlusion. Non-linear dynamic impact analysis was performed, simulating the right central incisor being impacted by a steel ball with a velocity of 10m/s. A functional chewing load (100 N) on the palatal surface of the central incisor was simulated for comparison. Displacements, strains and modified von Mises stresses were calculated for the adjacent teeth. During impact on the central incisor, the adjacent teeth showed root displacement. Considerable stress concentrations were observed on the palatal surfaces, proximal and labial surfaces of teeth adjacent to the traumatized incisor. Stresses in the adjacent teeth were higher than stresses calculated during functional biting. Compressive stresses were concentrated at the proximal areas of the adjacent incisors. High levels of deformation were found in the root dentin of adjacent teeth during the traumatic event. A frontal impact on an anterior tooth generated stresses at the roots of adjacent teeth. These stresses may play a role in clinically observed sequelae of teeth adjacent to traumatized teeth.

A Basic Numerical Peening Indentation Model with Geometric Indenter Based on Dynamic Impact Analysis

As shot peening is widely used to improve the crack resistance of various metals, it isimportant to have an accurate method to calculate the compressive residual stress produced by thisprocess. To this end, this paper presents a finite element (FE) model that includes an indenterdesigned from a dent profile. The results of compressive residual stress obtained by using thisindenter model and a normal shot impact model are compared. The indentation FE solution with anunmodified indenter is close to that obtained using the rigid shot (RS) impact model. The solutionfor the indentation FE model with a modified indenter closely matches that for an elasticdeformable shot (EDS) impact model. These results confirm the effectiveness of the indentation FEmodel based on the dent profile. This model can replace the present impact FE models to calculatethe compressive residual stress produced by shot peening.

A 2-D Axisymmetric Indentation Model for Peening Residual Stress in Metallic Material and its Experimental Verification

Various impact analysis models have been used for analytical prediction of peeningresidual stress. In this paper, a new approach based on finite element (FE) analysis was proposed topredict the peening residual stress through single indentation analysis using the dent profilegenerated on a shot-peened surface. Three analysis models (rigid, elastic, and plastic shots) werecompared each other, and the dent obtained in the plastic shot impact analysis model showed a dentprofile almost identical to that of the experimentally obtained dent. A rigid indenter modelconstructed using the dent profile obtained by dynamic impact analysis, and it integrated into thesingle indentation analysis model. The FE surface residual stress obtained in the center of the dentof the indentation analysis model was found to be almost identical to the surface residual stressmeasured by X-ray diffraction (XRD), thus verifying the validity of the proposed single basicindentation FE model based on impact analysis.

Damage and failure modes of railway prestressed concrete sleepers with holes/web openings subject to impact loading conditions

Prestressed concrete sleepers are essential to the structural integrity of railway track structures, redistributing wheel loads from the rails to underlying ballast bed while securing rail gauges for safe train traffics. In practice, drilled holes or web openings are usually generated ad hoc in sleepers to enable signalling equipment and cables at a construction site. These holes and web openings could however affect the structural integrity of sleepers, especially when they are exposed to impact loading. In fact, statistically, 15–25% of dynamic loading conditions are of transience and high-intensity by the nature of wheel-rail interaction over irregularities. This study is thus the world first to rigorously investigate the impact behaviours of railway sleepers with hole and web openings, which is critical to railway safety and reliability. In this study, three-dimensional finite element modelling using ABAQUS Explicit is used to comprehensively design and analyse the behaviour of prestressed concrete sleepers with various types of holes and web openings upon impact loading. Two different modelling techniques including concrete damaged plasticity model and brittle cracking model are also exercised to aid in this study. The results obtained show that the brittle cracking model provides better damage results as it can illustrate crack propagation very well until reaching the failure mode under impact loading. The findings illustrate a pathway to use brittle cracking model instead of concrete damaged plasticity model for dynamic impact analysis. Moreover, the outcome of this study will provide a better and new insight into the influences of holes and web openings on sleepers’ failure modes under impact loading so that appropriate guidance can be proposed to rail and track engineers in order to generate holes and web openings ad hoc in prestressed concrete sleepers without compromising their structural performance.

Dynamic analysis of impact on test platform

In this paper, the finite element model of impact test platform is established and analyzed by explicit central difference method. The relationship among different output energy has been obtained, which evaluated the validity of the finite element model and the simulation results. The total energy of the system is relatively constant. Meanwhile, there are two mutations in the kinetic energy, which is basically consistent with the experimental results. The energy change, stress and strain of the test platform during impact are analyzed. Ensure the strength of test platform meets the requirement.

Dynamic response analysis of the vertical elastic impact of the spherical rock on the metal plate

In the process of top coal caving mining, the metal sheet of the tail beam of the hydraulic support will vibrate when coal and rock particles start to impact the tail beam. In the impact between the particles and the metal plate of finite dimension, there are many complicated problems such as short duration of impact, rapid enhancement of transient stress, local large deformation of particles and macroscopic deflection of the metal plate are involved. However, the analysis of the contact force between the spherical particles and other objects is still simplified to the ideal Hertz contact problem. In order to study the real contact states of coal and rock particles impact on the metal plate, we simplified the working conditions from the coal and rock particles impact the tail beam in top coal caving mining to the system that spherical particles have similar properties to coal or rocks impact vertically on the metal plate. Based on the Flores contact theory and the energy absorbed by the bending deformation of the metal plate, the contact model of spherical rock at the compression stage was established. At the same time, we researched the initial yield stress and initial yield impact velocity of spherical rock that obeys the Drucker–Prager (D–P) criterion and proposed the approximate theoretical calculation method of maximum contact compression of spherical rocks. In the range of elastic impact velocity, the influence of impact velocity, restitution coefficient, material parameters and structure sizes on the dynamic response of the system were also analyzed. Finally, the correctness of the theoretical model has been verified by the virtual prototype simulation combined by ADAMS and Hypermesh. The research will provide the basic theory reference for the recognition technology of a single particle of coal or rock that based on the impact vibration of the tail beam.

Reduced modal state-space approach for low-velocity impact analysis of sandwich beams

Abstract The convergence problems of nonlinear dynamic impact analysis may be in some extent overcome by using the linear forms of contact laws. However, the full-scale finite element analysis of structures with linearized contact laws need high computational efforts. In this study, an efficient reduced modal state-space approach with low computational cost was introduced to predict the dynamic structural response of sandwich beams. A one degree of freedom spring-mass system was used to model the dynamics of projectile. Furthermore, the fully dynamic equations of the sandwich beam were obtained using a new high-order finite element formulation . The dimensions of the dynamic system were reduced based on the method of truncated combination of modes. Finally, the reduced dynamic equations were solved in the framework of state-space approach. The results obtained from the present formulation were compared with the available analytical and numerical results and good agreements found between them.

A Dynamic Relation Model Analysis of High-speed Impact and Sabot Strength

To understand how a projectile penetrates a sabot during a high-speed impact testing, which led to the failure of the impacting experiment, a dynamic model was built based on the interactions between the projectile and the sabot; and the bearing strengths of the sabot with varying impact speeds were analyzed. The correctness of the model was verified by an experiment. It shows that, with all the other conditions kept the same, the maximum stress between the sabot and the projectile increases with the decrease of the sabot mass, the increase of the projectile and impact speed.

Dynamic impact analysis of masonry buildings subjected to flood actions

The effects of floods on buildings described in terms of damage phenomena and collapse mechanisms are investigated. A comprehensive numerical approach simulating the fluid–structure interaction is herein proposed integrating (a) an ALE formulation, (b) a two-phase fluid flow, and (c) a refined finite-element structural modelling. Several potential structural failures are considered for the structure, whose activation conditions are discussed, in terms of both fluid and structural characteristics. A sensitivity study is performed in order to study the loading induced by the flood and the corresponding structural effects (e.g. internal stress/forces). A comparison between flood actions obtained through numerical simulations and with formulations available in literature is presented, with the specific purpose of emphasize the differences due to the dynamic amplification effects. As main novel results, dimensionless abacuses providing the structural safety factor as function of geometrical structural properties and inundation characteristics are provided. Such a result is very valuable both for researchers and practitioners in the field of flood risk assessment.

Hybrid Program Dependence Approximation for Effective Dynamic Impact Prediction

Impact analysis determines the effects that program entities of interest, or changes to them, may have on the rest of the program for software measurement, maintenance, and evolution tasks. Dynamic impact analysis could be one major approach to impact analysis that computes smaller impact setsthan static alternatives for concrete sets of executions. However, existing dynamic approaches often produce impact sets that are too large to be useful, hindering their adoption in practice. To address this problem, we propose to exploit static program dependencies to drastically prune false-positive impacts that are not exercised by the set of executions utilized by the analysis, via hybrid dependence approximation. Further, we present a novel dynamic impact analysis called Diver which leverages both the information provided by the dependence graph and method-execution events to identify runtimemethod-level dependencies, hence dynamic impact sets, much more precisely without reducing safety and at acceptable costs. We evaluate Diver on ten Java subjects of various sizes and application domains against both arbitrary queries covering entire programs and practical queries based on changes actually committed by developers to actively evolving software repositories. Our extensive empirical studies show that Diver can significantly improve the precision of impact prediction, with 100-186 percent increase, with respect to a representative existing alternative thus provide a far more effective option for dynamic impact prediction. Following a similar rationale to Diver, we further developed and evaluated an online dynamic impact analysis called DiverOnline which produces impact sets immediately upon the termination of program execution. Our results show that compared to the offline approach, for the same precision, the online approach can reduce the time by 50 percent on average for answering all possible queries in the given program at once albeit at the price of possibly significant increase in runtime overhead. For users interested in one specific query only, the online approach may compute the impact set for that query during runtime without much slowing down normal program operation. Further, the online analysis, which does not incur any space cost beyond the static-analysis phase, may be favored against the offline approach when trace storage and/or related file-system resource consumption becomes a serious challenge or even stopper for adopting dynamic impact prediction. Therefore, the online and offline analysis together offer complementary options to practitioners accommodating varied application/task scenarios and diverse budget constraints.

Mouthguard Biomechanics for Protecting Dental Implants from Impact: Experimental and Finite Element Impact Analysis.

The purpose of this study was to evaluate mouthguard shock absorption ability, strain, and stress generation during impact on dental implants placed in the anterior maxilla. The mouthguard material was also characterized. Sixty experimental models were created and divided into six groups (n = 10): implant type, external hexagon (EH) and Morse taper (MT); without and with two mouthguards (MTG), EVA custom-fitted (Ct-MTG) and standard self-adapted (St-MTG). The Shore A hardness, EVA sheet and mouthguard thickness, and elastic modulus were measured to characterize the mouthguard material. A strain gauge was attached to the palatal surface of the implant abutment, which was subjected to an impact test. Distortion of the abutment and implant was determined after impact from centroid displacements in standardized radiographic images. Two-dimensional finite element models were created to represent the six groups and were submitted to nonlinear dynamic impact analysis. The data were statistically analyzed using analysis of variance (ANOVA) and Tukey test (α = .05). Ct-MTG resulted in higher Shore A hardness (P < .001). After the heat-forming process, the St-MTG maintained the original thickness, but the Ct-MTG thickness had decreased. The elastic modulus of EVA was 18.1 ± 0.5 MPa. The mouthguard presence reduced strain values significantly (P < .001), particularly for Ct-MTG. There was no significant difference between implant connection types EH and MT (P = .547). The external hexagon abutment resulted in higher stress and micro-displacement values. The mouthguard was able to absorb 40% to 46% of the energy caused by the impact on the dental implant.

GPS receiver phase biases estimable in PPP-RTK networks: dynamic characterization and impact analysis

The integer ambiguity resolution enabled precise point positioning (PPP-RTK) has been proven advantageous in a wide range of applications. The realization of PPP-RTK concerns the isolation of satellite phase biases (SPBs) and other corrections from a network of Global Positioning System (GPS) reference receivers. This is generally based on Kalman filter in order to achieve real-time capability, in which proper modeling of the dynamics of various types of unknowns remains crucial. This paper seeks to gain insight into how to reasonably deal with the dynamic behavior of the estimable receiver phase biases (RPBs). Using dual-frequency GPS data collected at six colocated receivers over days 50–120 of 2015, we analyze the 30-s epoch-by-epoch estimates of L1 and wide-lane (WL) RPBs for each receiver pair. The dynamics observed in these estimates are a combined effect of three factors, namely the random measurement noise, the multipath and the ambient temperature. The first factor can be overcome by turning to a real-time filter and the second by considering the use of a sidereal filtering. The third factor has an effect only on the WL, and this effect appears to be linear. After accounting for these three factors, the low-pass-filtered, sidereal-filtered, epoch-by-epoch estimates of L1 RPBs follow a random walk process, whereas those of WL RPBs are constant over time. Properly modeling the dynamics of RPBs is vital, as it ensures the best convergence of the Kalman-filtered, between-satellite single-differenced SPB estimates to their correct values and, in turn, shortens the time-to-first-fix at user side.

The dynamic impact analysis of real estate tax merger on real estate enterprises supply

This paper adopts Vector Auto-regressive model to examine the dynamic influence of real estate tax reform on the enterprises supply from the current three main ideas of real estate tax merger. The result shows that there is not the same effect of enterprises supply by the real estate tax merger. And this effect can not be simply classified as positive or negative. It is sure that the effect is obvious in short term, but is not significant in long term. Therefore, the adjustment using real estate tax to the production behavior of the real estate business is effective in the short term, but is bad in the long term.

Dynamic impact analysis of DFIG‐based wind turbine generators on low‐frequency oscillations in power system

The increasing integration of wind turbines mainly doubly fed induction generators (DFIGs) introduces dynamic interaction with the conventional synchronous generators (SGs) affecting the damping of low-frequency electromechanical oscillations (LFEOs) in the system. This study presents a complete impact analysis of DFIG integration on system damping. The damping ratio sensitivity to inertia is used to evaluate the impact of DFIG integration on the critical modes. This study identifies that the impact could be positive or negative based on the location of DFIG. The results obtained are verified by detailed eigenvalue analysis and time-domain simulations for different operating conditions with three-phase fault. The negative impact on damping is improved by optimally tuned power oscillation dampers (PODs) with input signals obtained from the phasor measurement units. The impact on dynamic performance of the system due to removal of SGs and addition of DFIGs is investigated. The DFIG penetration is increased on the basis of participation of SGs in critical modes and the results of sensitivity analysis. The proposed approach is tested on standard IEEE 39-bus test system. The investigations carried out in this work can be employed for planning studies of power system integrated with DFIG for identifying their suitable locations and improving LFEO damping with their high penetration.

Dynamic impact force in an axial member with coupled effects of structural vibration and various support conditions

Longitudinal impact of a mass (or hammer) on a drill rod has been used over the years on a number of terrestrial applications such as pile driving, rock drilling, and soil testing as well as in drilling devices designed to explore the subsurface of Lunar, Martian, and other planetary bodies. Previous studies have investigated the effects of the boundary conditions on the wave propagation on the rod. However, the coupled effect of the dynamic response, damping and the boundary conditions of the rod on the contact/impact force has not been considered. This paper presents the dynamic contact analysis of the longitudinal impact of a mass on a rod with rigid, free, deformable, and slip support conditions including the effect of damping of the rod. Focus is given to capture how and under what conditions the impact force is affected by the support conditions. The contact force was obtained using Hertz force-indentation relation coupled with the structural vibration of the rod. Both the contact force and the rod dynamic response are determined using mode superposition method as well as an in-house finite element code. A very good agreement is found between the results from the two methods. The results are verified with experimental data previously available in literature and using Abaqus FEA. It is found that for the undamped case the force is affected by the support condition only if the duration of contact between the striker and the rod is larger than the time that the displacement wave takes to travel through the rod to the other end and return back to the contact end. On the other hand, when damping of the rod is considered the contact force is observed to be affected by the support condition before the arrival of the reflected wave to the contact end. However, the effect of the support conditions in the damped case is significantly higher when the duration of contact is larger than the time of arrival of the reflected wave from the far end. When the rod penetrates into the supporting medium while the contact is present the contact force decreases at a higher rate compared with the case where penetration is not present during contact.

Dynamic analysis of global warming impact of the household refrigerator sector in Japan from 1952 to 2030

The household refrigerators consume large amounts of energy and emit vast refrigerants which contribute to global warming indirectly and directly. The intervention of energy efficiency standard, aging process, and refrigerants substitution result in the performance of the household refrigerator sector varying with time. The present study analyzed dynamic global warming impact of the household refrigerator sector in Japan from the 1950s to 2030 taking into account both the energy effect and chemical effect. The energy effect modelling integrated energy efficiency improvement over year and energy efficiency deterioration over age. The chemical effect modelling involved substitution of three generations of refrigerants on the basis of the flow and stock model. The results showed that the global warming impact of the household refrigerator sector peaked at 25,104 kt CO2 eq. in 1990 and then decreased to 6506 kt CO2 eq. in 2030. The energy effect accounted for at least 91% and this ratio would be much higher in the future. Both implementation of minimum energy efficiency programs and substitution of refrigerants reduced the global warming impact significantly. This dynamic analysis could provide a holistic picture of the global warming impact of the household refrigerator sector both retrospectively and prospectively from accessing to the market, through rapid growth, to saturation.

Numerical investigation of CFRP strengthened full scale CFST columns subjected to vehicular impact

In recent years, the risk of damage or failure of axial load bearing structural members has increased rapidly due to increase of accidental vehicle/ship collision events. Therefore, suitable strengthening technique needs to be developed to minimise the casualty and economic loss caused by vehicular collisions with structural columns. In this study, numerical simulations are carried out to evaluate the effect of carbon fibre reinforced polymer (CFRP) strengthening of full scale concrete-filled steel tubular (CFST) columns under vehicular impact. Numerical models of bare and CFRP strengthened CFST columns were first developed and validated in a recent study of the authors. The validated finite element (FE) models are extended to full scale columns. Realistic vehicle behaviour is simulated with simplified mass-spring vehicle model. The outer diameter of steel section is kept same and the wall thicknesses are changed to account the slenderness effects of hollow steel sections. Both vehicle and column deformations are considered during the impact simulation as observed in practical situation. The dynamic impact analysis results show that adhesively bonded CFRP sheets provide enhanced impact resistance capacity of strengthened columns by reducing lateral displacement about 40% compared to ordinary CFST columns. A comprehensive parametric study is conducted by varying the vehicle velocity, vehicle mass, axial static loading, vehicle stiffness and CFRP bond length to observe the effects of these parameters on the structural responses of bare and wrapped columns. CFRP wrapping is found to be a promising strengthening technique to control global failure of full scale CFST columns subjected to vehicular impact.